将时间（hh：mm：ss）添加到SQL中的datetime字段

Question

我想将run_duration列（hh：mm：ss）添加到run_datetime（datetime）列，以使用以下查询计算结束时间：

SELECT checkdate, run_datetime, run_duration,
cast(run_datetime as datetime) + cast(run_duration as datetime) as readytime, 
cast(cast(run_datetime as datetime) + cast(run_duration as datetime) as datetime) as readytime_datetime
FROM table

问题在于它没有为某些记录正确添加，因为它总计超过60秒：

还有其他方法可以正确地执行此操作吗？

Answer 1

使用MySQL内置的addtime()函数代替+运算符：

SELECT checkdate,
       run_datetime,
       run_duration,
       addtime(cast(run_datetime as datetime), cast(run_duration as time)) as readytime
FROM table

+运算符将日期时间转换为数字并将其相加。